"...Although the independently-developed reduction gear tends to attract the most attention, P&W says the GTF core also features advanced technology, including a second-generation "super cooling" for turbine blades. That system improves on first-generation super-cooling originally developed for the F-35 Joint Strike Fighter's F135.

"We are working on turbine cooling technologies that are over and above what's in the F135 today," Croswell says.

The PW9000 series will not be the only beneficiary of GTF-derived technology. The F135 itself is poised to be eligible for a series of technology upgrades.

On 23 February, the Air Force Research Laboratory (AFRL) awarded P&W an $11.8 million contract to test an engine demonstrator. The contract pays for 50h of high-cycle fatigue tests on the XTE68/LF1 performance demonstrator, which is based on the short take-off and vertical landing version of the F135.

"We're putting some hot section technologies into the combustor and in the high-pressure turbine, and some [aerodynamic] technologies into the low-pressure turbine. Those are the technologies we are demonstrating," Croswell says.

The aerodynamic change consists of a new high-lift design for the stationary turbine vanes that reduces their numbers and lowers the engine's overall weight, improving specific fuel consumption.

More importantly, P&W is integrating a second-generation cooling system derived from GTF technology: a civil market feature being added to the world's most advanced military engine.

The new cooling system "will enable us to provide even lower pattern factors, so it's the profile and temperature end of the turbine," Croswell says. "So we have to design the turbine such that it can take the heat temperature profile. If we can flatten the profile out so there's no spikes, we could run even hotter engine temperatures."

One way to increase maximum thrust is to combust the fuel and pressurised air at hotter temperatures, but there are other benefits. Engine components that can survive at hotter temperatures can also last longer if thrust is not increased. Alternatively, the airflow extracted to cool the engine can be reduced, lowering specific consumption.

"The goal is to provide options. We have the temperature capability to go to more thrust if needed - or we could go to more durability or reduce cooling air and have better fuel consumption," Croswell says.

The AFRL and the US Navy are funding the XTE68/LF1 demonstration, but the F-35 programme has yet to commit to integrating the upgrades, even if they are proven to work.

"You have to divorce this from the JSF programme," Croswell says. "The JSF programme is aware of it and endorses it, but this is an AFRL/US Navy-funded technology programme."

The F135 is required to provide 43,000lb of thrust in afterburner mode. The XTE68/LF1 is demonstrating a thrust improvement between 5% and 10%, potentially raising the single-engined fighter's overall performance from more than 45,100lb thrust to 47,300lb thrust.

Before GE's alternative F136 programme for the F-35 was cancelled last year, P&W's rival made a talking point out of the existence of a thrust improvement programme for the F135. After all, the USAF's F-35A will not enter service until at least 2018, and its only engine supplier is already working on a thrust upgrade. [GUMS quote below]

However, Croswell insists the XTE68/LF1 simply fits the historic pattern.

"It's kind of what we've done in the past. Through the technology programmes we demonstrate the capability, and then the JSF programme will decide if they want to transition," Croswell says. "We did that on the F100. We proved that technology. We increased the life by 50%. That's our [enhanced engine performance] package."...

...P&W eyes durability lift for stovl F135PRATT & WHITNEY has quietly received approval to launch a second engine demonstrator focused on inserting durability improvements into the short take-off and vertical landing (STOVL) version of the F135.

The XTE69/LFU1 demonstrator aircraft will in late fiscal year 2014 begin testing upgrades, with P&W confirming that it entered production. The company's XTE68/LF1 demonstrator will enter testing in the fourth quarter of this year.

Durability has been an issue for early STOVL engines. Although the baseline version is performing as designed, unexpected heat or friction caused P&W to make three changes effecting the driveshaft, lift-fan clutch and roll-post actuator nozzles to successfully release the F-35B from probation last year."

More engine MumboJumbo at the JUMP!

Last edited by spazsinbad on 29 May 2012, 23:18, edited 1 time in total.

After all, the USAF's F-35A will not enter service until at least 2018, and its only engine supplier is already working on a thrust upgrade.

I throw the BS flag.

The "A" will be operational a lot sooner I also think that the "B" will also.

Despite the concurrency issue, I can not imagine more than two years for the first F-35 operational wing to have an ORI. By next summer, we will have had the weapon release testing and high AoA testing and such stuff behind us. And I can not see any major problems there. The helmet and the hook on the "Cee" bother me more.

Having flown three jets in the first year of development, I have seen the ability of the contractor to respond to problems and fix things.

Gums sends...

Gums
Viper pilot '79
"God in your guts, good men at your back, wings that stay on - and Tally Ho!"

Lightndattic wrote:P&W gets a government contract to do research into improvements to their engines, but cries foul when GE gets a research award under the ADVENT initiative?

I was upset as a taxpayer seeing a company that is 90% 'Non-North American' getting the ADVENT contract (RR North America) from the USAF.

Yet another reason GE/RR shouldn't complain about loosing the F136 program when they're getting USGov funding to further their R&I programs.

Seems PW has been doing this on their own any how. If you read through the article, their internal/civil programs have surpassed the (USGov Funded) F135 technology already. (Without the ADVENT/HEETE contract in question) Planning where/how/why to make more thrust with increased savings without the DOD/FMS customers asking for it. PW learned their lesson well in the 80's

TEG

[Airplanes are] near perfect, all they lack is the ability to forgive.
— Richard Collins

"General Electric and Rolls-Royce's decision to abandon their fight for an alternate engine to power the F-35 Joint Strike Fighter finally put an end to a long, politically charged battle with incumbent Pratt & Whitney. Or did it?

No, the GE-Rolls F136 is not rising from the dead. But a U.S. Air Force demonstrator program, in which GE, Rolls and Pratt are competing separately to develop fuel-saving propulsion technology for combat aircraft, could conceivably produce an alternate engine sized for the JSF as early as 2020. That possibility has sent jitters through Pratt and its allies on Capitol Hill...."

"General Electric and Rolls-Royce's decision to abandon their fight for an alternate engine to power the F-35 Joint Strike Fighter finally put an end to a long, politically charged battle with incumbent Pratt & Whitney. Or did it?

No, the GE-Rolls F136 is not rising from the dead. But a U.S. Air Force demonstrator program, in which GE, Rolls and Pratt are competing separately to develop fuel-saving propulsion technology for combat aircraft, could conceivably produce an alternate engine sized for the JSF as early as 2020. That possibility has sent jitters through Pratt and its allies on Capitol Hill...."

LOTs Lots lots more at the jump.

If the new engine technology presents a compelling case for implementation in the F-35 down the road, so be it. Maybe it will put a significant dent in that $1 Trillion-plus lifetime program cost. May the best engine tech win.

popcorn wrote:If the new engine technology presents a compelling case for implementation in the F-35 down the road, so be it. Maybe it will put a significant dent in that $1 Trillion-plus lifetime program cost. May the best engine tech win.

"General Electric and Rolls-Royce's decision to abandon their fight for an alternate engine to power the F-35 Joint Strike Fighter finally put an end to a long, politically charged battle with incumbent Pratt & Whitney. Or did it?

No, the GE-Rolls F136 is not rising from the dead. But a U.S. Air Force demonstrator program, in which GE, Rolls and Pratt are competing separately to develop fuel-saving propulsion technology for combat aircraft, could conceivably produce an alternate engine sized for the JSF as early as 2020. That possibility has sent jitters through Pratt and its allies on Capitol Hill...."

LOTs Lots lots more at the jump.

If the new engine technology presents a compelling case for implementation in the F-35 down the road, so be it. Maybe it will put a significant dent in that $1 Trillion-plus lifetime program cost. May the best engine tech win.